Unusual thiophilic ring-opening of fused oligothiophenes with organolithium reagents
作者:Konstantin Chernichenko、Nikolai Emelyanov、Ilya Gridnev、Valentine G. Nenajdenko
DOI:10.1016/j.tet.2011.06.082
日期:2011.9
Organolithium reagents attack the sulfur atoms of fused oligothiophenes producing ring-opened organolithium intermediates that can be trapped with a suitable electrophile. The reaction was found to be general for fused thieno[2,3-b]-thiophenes and some [3,2-b]-fused oligothiophenes. Thermodynamic (organilithiums basicity) and mechanistic (RLi coordination by neighboring sulfur) aspects control the
有机锂试剂攻击稠合的低聚噻吩的硫原子,产生可被合适的亲电试剂捕获的开环有机锂中间体。发现该反应对于稠合噻吩并[2,3- b ]-噻吩和某些[3,2- b ] -融合的低聚噻吩是普遍的。热力学(有机锂的碱度)和机理(RLi通过相邻硫的配位)方面控制反应的底物范围和区域选择性。当可以使底物竞争性去质子化时,与其他测试的有机锂相比,使用n -BuLi可观察到对开环的高选择性。最近发现的八硫代[8]环戊烯可产生多种开环产物。